The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Oct. 26, 2010
Filed:
May. 22, 2007
Mehdi Abolhassani, Timonium, MD (US);
Shailesh P. Waikar, Cockeysville, MD (US);
Ren H. Wang, Timonium, MD (US);
Uday S. Deshpande, San Diego, CA (US);
Mehdi Abolhassani, Timonium, MD (US);
Shailesh P. Waikar, Cockeysville, MD (US);
Ren H. Wang, Timonium, MD (US);
Uday S. Deshpande, San Diego, CA (US);
Black & Decker Inc., Newark, DE (US);
Abstract
A power tool may include an electronically commutated motor such as, for example, a brushless DC permanent magnet motor with a rotor having internally mounted magnets and/or cavities filled with air or other non-magnetic materials. A control system may be used to control the motor in a manner that implements field weakening when the speed of the motor increases beyond its rated motor speed, or when the torque demands on the motor continue to increase after the maximum power output of the motor is reached. The field weakening may offset the growing back EMF and may enable a constant power and constant efficiency to be achieved by the motor over a wide speed range, rather than at just a single predetermined operating speed. Pulse width modulation control of the motor may be used up until the motor reaches its maximum power output.